# Multi-sensor fire detector plan symbol

Canonical URL: https://eloragrid.ai/symbols/iec-multi-sensor-detector-plan-symbol
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: MSD
Drawing use: GA
Reference families: IEC

## Symbol convention

Convention: IEC
Form: Multi-sensor detector
IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

Fire alarm plan symbol for a detector combining smoke and heat sensing, often switchable between modes.

## In plain English

### What does Multi-sensor fire detector plan mean?

Multi-sensor detectors combine optical smoke and heat sensing, and sometimes carbon monoxide, in one head. Plans draw the detector box with both smoke and heat marks, or a tag such as MS, so the installer fits the correct head.

### A simple example

These detectors reduce false alarms while keeping smoke sensitivity, and some can be programmed to act as heat only at certain times. The plan symbol therefore often sits alongside a cause-and-effect note. The symbol does not show the programmed mode. The fire alarm configuration records that.

### What the drawings help you do

Check programmed modes in the configuration notes. Confirm the base type matches the panel protocol. A single-sensor smoke detector has one mark; the multi-sensor shows both smoke and heat elements.

### This particular reference

Fire alarm plan symbol for a detector combining smoke and heat sensing, often switchable between modes. A single-sensor smoke detector has one mark; the multi-sensor shows both smoke and heat elements.

### Terms

- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)
- [Electrical installation design methodology and references](https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design)


## What it represents

Multi-sensor detectors combine optical smoke and heat sensing, and sometimes carbon monoxide, in one head. Plans draw the detector box with both smoke and heat marks, or a tag such as MS, so the installer fits the correct head.
These detectors reduce false alarms while keeping smoke sensitivity, and some can be programmed to act as heat only at certain times. The plan symbol therefore often sits alongside a cause-and-effect note. The symbol does not show the programmed mode. The fire alarm configuration records that.

## How to read it

- Check programmed modes in the configuration notes.
- Confirm the base type matches the panel protocol.

## Information to show or reference

- State sensing elements.
- State programmed mode.
- Tag loop and address.

## Important distinction

A single-sensor smoke detector has one mark; the multi-sensor shows both smoke and heat elements.

## Facts

- Sensing: Optical smoke plus heat, sometimes CO
- Benefit: Fewer false alarms
- Exact standard graphic: Not reproduced here; confirm the form against IEC 60617 and the project legend

## Public references

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC graphical symbol context for installation plans; independently drawn here.
- [Electrical installation design methodology and references](https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design) — Schneider Electric — Electrical Installation Guide. Installation design context: life-safety systems are coordinated with the building electrical design.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.